AO Smith Z8 Water Purifier Review (After 3 Years)

Usually, you find users posting reviews immediately after purchasing any product. Now tell me, how can you judge an appliance’s performance within days of buying it? You have yet to explore the full features. So, the review is bound to be biased because every product works excellently initially. The true colors emerge only after you use them continuously for some time.

In this context, our review of the AO Smith Z8 water purifier is genuine because we have been using this machine for nearly three years.

AO Smith z8 hot ro

Our opinion regarding the AO Smith Z8

We have been using this water purifier for three years now, and the performance is excellent. The best feature is the ability to deliver water at three different temperatures.

You get water at room temperature for drinking. However, in this era of the pandemic, some people prefer to have warm water. So, this machine gives you warm water at 45 degrees Celsius. In addition, you can obtain hot water at 80 degrees Celsius, stored in a stainless-steel tank inside the machine, for cooking purposes.

Yes. We agree maintenance costs are high at Rs 5,000 per year. But, considering the TDS levels and water quality in our source water, the AO Smith Z8 is the perfect machine.

Ao smith z8 hot water purifier

General Advice – Regarding the choice of water purifiers for your home

Every house has varying requirements. Much depends on the water source and the quality of water you receive in your taps. Water from ground sources like tube wells contains high TDS levels.

Similarly, the groundwater quality near coastal areas could be better because of the high volume of TDS. Homes near industrial areas get water contaminated with heavy metals. So, a RO+UV+UF should be the ideal water purification mode,

Municipalities in many cities/towns supply RO-treated water to their residents. Under such circumstances, spending money on an RO water purifier is a criminal waste because the water does not have high TDS levels. Such water can get contaminated with bacteria and other microbes. So, a UV water purifier should be perfect.

best tds in drinking water

Therefore, we recommend testing the source water for TDS levels is paramount before selecting your water purifier. If the TDS levels are below 300 ppm, you need not waste money on an RO water purifier. Instead, a UV water purifier, like the AO Smith Z1, should be ideal. The plus point is that this model also supplies hot and normal water, like the AO Smith Z8.

At this point, we like to add that AO Smith has introduced a new model, Z9 Hot+, an improvement over the AO Smith Z8 model. We will discuss it in a separate review. However, we shall concentrate on the Z8 model in this review.

We shall begin our review of the AO Smith Z8 by discussing its pros and cons.

AO Smith Z8 RO review

Benefits of AO Smith Z8

  • As mentioned above, this machine can deliver water at three different temperatures for varying purposes.
  • This machine uses a patented side stream RO membrane to ensure 100% water passes through the membrane to eliminate any chance of contaminants passing through.
  • This water purifier uses an innovative Silver Charged Membrane technology (SCMT) to prevent secondary microbial contamination after RO purification.
  • The ZX dual filter comprising Silver Activated Post carbon (SAPC) filtration plus SCMT ensures high-quality purification.
  • The innovative Night Assist feature allows you to locate the appliance in the dark because switching on this feature emits a blue light directing you towards it with ease.

Drawbacks of AO Smith Z8

  • This machine has a unique mechanism to obtain hot water, lifting the faucet upwards and pressing the child lock button. This procedure takes time to get used to.
  • If you place the machine on the kitchen counter, there is not enough space to fill the water in a one-liter bottle. The solution is to mount the machine on a stand at a higher level.
  • The hot water tank capacity could have been better because the hot water only flows once the tank is full.    

Let us now review the AO Smith Z8 from a user’s perspective.

Related Reading

Filtering Technologies – It’s the same everywhere.

AO Smith Z8 RO

All RO water purifiers work on similar 6-stage or 8-stage filtering technologies, depending on the number of filters available in the machine. The AO Smith Z8 offers an 8-stage purification process. However, the RO purification procedure in the Z8 differs from that in models like Kent, Havells, Aquaguard, etc.

RO purification – A unique change

Usually, the source water enters the RO membrane from the top or one of the ends of the membrane and moves through it to remove TDS. As a result, the initial part of the membrane is overexposed to water with TDS. Therefore, the membrane wears down quickly, requiring frequent replacement. Let us see how the AO Smith Z8 is different.

AO Smith Z8 RO Water purifier

The Z8 has a unique mechanism where the source water enters the RO membrane from the sides. So, the membrane has a uniform water distribution before it flows out from the opposite side. It ensures that no part of the membrane is overexposed to TDS water. Thus, it extends the membrane’s life, incurring fewer maintenance costs.

Water wastage – Invariable

Z8 Filter

All RO water purifiers waste a lot of water because the purification process is such that water wastage is invariable. However, much depends on the TDS levels in the water source. Higher the TDS levels, the more the wastage. Therefore, ascertaining the TDS levels in the source water is crucial before investing in any RO water purifier.

AO Smith has patented a new technology, Advanced Recovery Technology (ART), which they claim saves water. It may be true, but it is better than the Zero water wastage claim made by Kent RO, where the machine recycles the rejected water into the overhead tank. Nevertheless, the TDS levels in the water source determine the quantum of water wastage.

AO Smith z8 Taps

Double protection filter – An innovative technology

AO Smith Z8 offers a ZX Double protection filter comprising SAPC and SCMT, harnessing the anti-microbial powers of silver to provide healthy drinking water. Having used other water purifiers before, we experienced a different taste to the water purified by AO Smith Z8.

SCMT is an advanced technology compared to UV filtration. MIN-TECH (Mineralizer Technology) replenishes lost minerals after RO purification might be the reason. However, the water tastes good after purification.

Hot water facility – The highlighting feature

Hot water at 81c
Hot water at 81 Degrees

Some latest water purifiers offer a hot water facility, but the AO Smith Z8 is the best. The appliance has two options for delivering hot water. One is warm water at 45 degrees Celsius, and the other is hot water at 80 degrees Celsius for cooking purposes. Let me share a hack enabling you to get water at any temperature you want.

Suppose you need water at 50 degrees Celsius. Press the red button until the LED shows 45 degrees. You will hear three beeps, and the machine will stop heating the water. You must press the red button again for three seconds to set the temperature to 80 degrees Celsius. However, as soon as the temperature reading shows 50 degrees Celsius, you can press the red button to stop the heating at 50 degrees Celsius.

AO Smith z8 hot water

The hot water facility makes this machine one of the best available. However, it takes time for users to get used to obtaining hot water. For example, I experienced some problems initially when lifting the faucet to obtain hot water because the water used to spill out. But I have now mastered raising the faucet quickly and avoiding water spillage.

However, the machine has a significant drawback. It does not deliver the hot water until the stainless-steel tank gets filled with hot water. In addition, the hot water facility consumes around 24 watts of power. Therefore, this water purifier consumes more power than other models that do not offer a hot water facility.

AO Smith z8 hot water dispenser

Auto Cleaning Feature – A good one

One of the better aspects of the AO Smith Z8 is the auto RO membrane cleaning feature. When you start the machine, the water flows into the membrane to clean it thoroughly. Then, the water gets flushed out, with the LED indicators signaling the same. This feature enhances the RO membrane life.

Advance Alert System – A helpful feature

The AO Smith Z8 has an advanced alert system that lets you know when to change the RO membranes and other filters. Thus, you get sufficient time to arrange for their replacement.

Installation – Simple

The installation procedure is straightforward. You can mount the machine on the wall or the countertop. However, I suggest placing the machine on a stand mounted on the wall at a reasonable height. It enables you to get water without any inconvenience.

Warranty – Peace of mind

AO Smith offers a one-year warranty on the product. This comprehensive warranty includes changing the RO membrane and filters if necessary. Take an AMC with the authorized AO Smith service center to ensure prompt replacement of RO membranes and other filters regularly. It helps extend the machine’s life. The approximate maintenance cost is around Rs 5,000 annually.

Is it better than the Z9?

The AO Smith Z9 model is an improvement over the Z8 model. It has sensors, whereas the Z8 does not. However, the Z9 has a significant drawback. It cannot dispense water without a power supply, whereas the Z8 can do so.

FAQ – AO Smith Z8

1. Can we adjust the TDS levels of the output water according to our convenience?

No. The AO Smith does not offer any such facility. Instead, it removes maximum TDS, and the MIN-TECH technology replenishes the lost minerals to improve the water taste.

2. Does the AO Smith Z8 offer UV filtration?

No. The AO Smith Z8 does not have the UV filtration feature. Instead, it uses SCMT to kill microorganisms and make the water 100% safe and hygienic.

3. What is the storage capacity of the AO Smith Z8 water purifier?

The AO Smith Z8 has an overall storage capacity of ten liters, which should be sufficient for small and medium-sized families. The hot water storage capacity is one liter.

4. Should we keep the Z8 switched on all the time?

Yes. It is advisable to keep the Z8 switched on 24 x 7 because the auto flush function will start every time you switch on the machine. However, that could lead to water wastage.

5. Does it require a running water supply?

Yes. This water filter requires a running water supply. The tank starts refilling as you remove water from it. The water level indicator displays the water level all the time.

6. What is the water purification rate of the AO Smith Z8?

This water purifier can purify 15 liters of water in an hour.

7. What can you use the hot water for?

Warm water at 45 degrees Celsius is ideal for drinking immediately. Water at 80 degrees Celsius is equivalent to boiling water. You can use it for preparing tea, coffee decoction, and cooking.

8. Does the AO Smith Z8 give cold water?

No. The AO Smith Z8 gives water at room temperature. It does not offer water chilling facilities.

9. How often do the filters need replacements?

The pre-filter needs replacement every three to six months. The other filters can work for 9 to 12 months, depending on the TDS levels in the source water. The average maintenance costs are Rs 5,000 annually.

10. How is the Z1 different from the Z8?

The Z8 model is RO + SCMT, whereas the Z1 model is a UV water purifier. It does not offer RO water purification.

Water Taste
Water Savings
Installation & Service
We have been using this water purifier for three years now, and the performance is excellent. The best feature is the ability to deliver water at three different temperatures.
Geetha Srinivasan
Geetha Srinivasan
Geetha Srinivasan, a retired homemaker, holds a Bachelor's degree in Food Science and Technology From Anna University. She is a culinary and kitchen appliance expert with an impressive 30 years of experience in testing kitchen appliances like Mixer Grinders, Juicers, Food Processors, Air Fryers, and Ovens, Beyond appliances, she excels in kitchen organization, cleaning, and cooking, delighting family and friends with her culinary skills. At 55, her passion for all things culinary burns bright.


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We have been using this water purifier for three years now, and the performance is excellent. The best feature is the ability to deliver water at three different temperatures. AO Smith Z8 Water Purifier Review (After 3 Years)